Ship stabilizers



Jan, 24, 1961 J. v. Fou. 2,969,035

SHIP sTABILIzERs Filed June 19. 1959 2 sheets-sheet 1 @1.24, 1961 H.POLL 2,969,035

SHIP STABILIZERS Filed June 19, 1959 2 Sheets-Shet 2 2,969,035 simsr'Annii'zEns .lohn Victor Fell, Beckenham, England, assigner toMuirhead d: Co. Limited, Beckenham, Kent, England Filed rune 19, 1959,ser. No. 821,521 Claims priority, application 'Great Britain May 20,1959 '3 Claims. (Cl. 114-126) This invention relates to devices forstabilizing' or damping the roling motion of ships' and in particular tosmall ships and yachts by means of fins projecting laterally, from eachside o-f the ship below the' water line. Such fins are normally ofhydrofoil section and their planes are parallel to the now of water pastthe ship when in forward motionL so that they do not react with thewater, that is to say, they'present zero angle of incidence to the waternow. However, in order that the tins may act to stabilize the ship theangle' of incidence of the fins may be adjusted positively andnegatively, i.e. they may be tilted in such a manner that the ensuingforce due to the reaction between the fin and the water continuouslyopposes the sea forces causing the ship to roll. In this way the rollingmotion is limited to a very small degree.

A power means to actuate' the nns is provided which may be hydraulic,electric or steam operated or combinations of the same. A well' knownsystem uses `hydraulic rams supplied by available delivery pump. Thepower means and hence'the iin angle is controlled by a sensing meanswhich measures one or more of the' functions of the roll, c g.displacement, velocity or acceleration and provide a control' signalproportional to a' single function or a combination of said functions.

Such power means and sensing means are well known and do not form apartof the present invention.

The invention relates to' an' ar'rangemeritV in which a plurality offins are provided` dde'ach side of the' ship, suitably placed and ofsu'cl'l dimensio'nsrtliat' 'they'no 'not materially interfere withnormal operation' and vmano'e'vring. Thus, they are placed at thecirvd'sec'tion between the Vertical `sides and sensibly' horizontalbottoni, and do not extend beyond the projection of these surfaces.

in other such arrangements such fins' are erected on and held to theside of the ship by` longitudinal'nieinbers and \\Abrackets or similarstiffening arrangements to withthrough the water. v

The invention relates'tol a part ul'ar nn construction one object ofwhich is the avoidance' of hydrodynamic inefliciency due to the use ofextraneous supports'. The omission of said extraneous supports alsoavoids a serious ineiciency in respect of the lift of the liris whichwould occur due to the upwardly'and downwardly moving Water (afterde'lle'xionV by tli'e'nns) striking such supports and causing anopposing liftwhich'would'subtfact from the total lift available from thewhole nn assembly.

The-invention consists of a ship lstabilizer n arrangement comprising aplurality of tins' provided along the side of the ship each iin beings'lippor' 'd for rotation about a stub-axle the ns havingcranliseecure'dthereto, in which the crank'sare linked by a connecting rod forsimultaneous operation.

Each nn is supported on the equivalent o'f ay stub 'axle or pintleproviding either asinglelongbearing or two bearings co-'operating withbearing' surfaces internal to the lin, such bearing surfaces beingtidefrom a' suitable stand the forces generated by the nn's dueto theirpassage g'rade' of hard rubber, resin impregnated fabric or othersubstance which provides a suitablev bearing surfaee'with water actingas the lubricant, allowances being made in the ntting of the bearingsfor swelling which may take place under conditions of continuousimmersion in water. A suitable resin impregnated fabric ris available,under the trade name Tufnol.

In the construction the pintle and tinv are both in the form of castingsand the pintle is provided with a groove or flange which engages with asplit ring of TufnoL for example, for the purpose of retaining the tinor the pintle. Access to the bolts for securing the split ring may beobtainedV through holes suitably placed in the base of the pintle. Thesection through'the nn may Vary from the inner to the outer portions,the inner portion beingy the deeper section in order to accommodate alarger bearing where' the bending moment of the-pintle is greater andhence, la larger diameter of pintle is required.

Since the connecting rods must operate alternately under compression andtension,r they are ypreferably made of large diameter. The rods arepreferably formed of sections and ends of adjacent rod sections maybeconnectedby a flexible joint nthe'form of a split moulding of toughrubber, the moulding engaging with the spherical end of a crank pinattached to the extremity of the fin crank. The flexibility of lthisjoint enables the system of connecting rods to respond to flexures inthe ship structure andv further, to operate a system of ns mounted on acurved surface of the ship, each connecting rod being straight initself.

The fins are preferably spaced suniciently far apart from each other sothat interference of one tin on a succeeding nn or nns is reduced. StiIlfurther to diminish this effect the ns subsequent to the first may bedellected through a larger angle'. By way ofexample, the second, thirdand fourth nns might operate through angles progressively greater thanthe rst, with subsequent nns all operating at the same angle.

The movement of the lins'is controlled by a controlling means and apower means as hereinbefore referred to, the mechanical motion froml-the power means being passed via a shaft through the hull to a crank onone of the connecting rodsdisposed among-the group of ns. On largerships there may be two or' more controls per side but on small shipsoneAv control' n'nit could' operate all the req'uired tins'.

The nn's may be' subjeot to'l damage fromfloatin'g'objects, or -in thecaseV of s"tfrandi-'r1g',-the ship may heel over and rest on theV iins;To yavoid structural damage to the ship it isa feature of the inventionto make the` pintle definitelyl weaker' than its attachment to thesidedf the ship so thatin the' event vvof' overs'tr'ining, tlieiins`will break off beforedarnge is Cn's'ed to the hull. Asi an example,wherethe normal s'tressonthe pintle is 2 tons per in.2, they breakingystressA may be made'- l5 tons per in?.

It is desirable that'thens" and all operating parts' which are exposedto the water aremadeof non-corrosive material such Ias Monel 4metal'althoughv stainless steel may alternatively be used for all o'r sorn'eportions, for example, the connecting rods anclpintles. Alternatively, afabricated construction by' `vv'eldin'g may be used instead of castings.The-surfacesy whichare' notoperating' or bearing surfaces mayalternatively be'of other materials covered witha protective'coatingsuehas'- rubber or plastic having botliprotectivef andantiifolingproperties.

The invention will now be further described with reference to thedrawings in which:

Figure-l is apart section through a'n,

Figure .is a plan'of ann,

Figure 3 is' an elevation of afin,

Figure 4 shows a group of ns attached to a ships side,

Figure 5 is an alternative arrangement of fins,

Figure 6 is an elevation of a iin in accordance with the arrangement ofFigure 5,

Figure 7 is a section olf part of a ships hull showing a fin assembly inlaccordance with the arrangement of Figure 5,

Figure 8 is a flexible coupling,

Figure 9 is an alternative exible coupling,

Figure l is a detail of a crank.

Figure l shows pintle mounting plate 1 bolted to ships side 2 andsupporting pintle 3 disposed within n 4. Pintle 3 is tapered andprovided with a bearing surface 5 at its extremity and a further bearingsurface 6 of larger diameter at the inboard end. Fin 4 is rotativelysupported on pintle 3 by bearings 7 and S engaging with bearing surfacesand 6 respectively.

Shoulder 9 adjacent large bearing surface 6 together with the reduceddiameter lil of pintle form a groove or slot containing split ring 11which is further enclosed by an annular recess 12 in the inboard end ofn. Bolts 13 suitably disposed round the outer edge of split ring 11secure the latter to fin. Thus, the fin is secured to the pintle by thesplit ring but is free to rotate about said pintle on bearings 7 and 8.Fin 4 and pintle 3 may be of cast construction in a non-corrosivematerial such as Monel metal or stainless steel. Bearings 7 and S andsplit ring 11 are of hard rubber or resin impregnated fabric, andbearing clearances a, b, c or d are water lubricated and adjusted toallow for swelling of the bearing material due to water immersion. Hole14 drilled concentrically in the i-nboard end of pintle 3 is provided toreduce the strength of said pintle to a degree that will allow thepintle and n to break olf in an emergency without damage to the shipstructure. Holes 15 drilled Ithrough the pintle mounting plate 1 giveaccess to bolts 13 when securing the n to its pintle. Angular motion isimparted to the lin over crank 16 terminating in crank pin 17. The crankmay be formed integrally with the iin or welded or otherwise attachedthereto. The end of crank pin is in the form of a sphere or knuckle lwhich engages with spherically formed exible joint 19 in the assembly ofconnecting rods and indicated in the gure by the broken line surroundingthe knuckle.

Figure 2 is a plan and Figure 3 is a-n elevation of the n assemblywherein like reference characters refer to like parts in Figure l.

Figure 4 shows an assembly of fins 4 arranged along the curvature of aships side 2 and actuated by connecting rods 20. Flexible joints orcouplings 19 linking adjacent connecting rods enable said connectingrods to take up positions tangentially to the curvature of the hullwithout imparting undue strain. Longitudinal motion for actuating thefins is imparted to said connecting rods by shaft 22 passing throughwatertight gland 23 to the outside of the ship and terminating in acrank. This structure is shown in greater detail in Figure 10 in whichshaft 22, operated at its inner end by the power means (not shown)passes to the outside of the ship through watertight gland 23. The outerend of shaft 22 terminates in crank 24 having a forked end. This forkedend engages two abutments 25 on connecting rod 20 whereby rotary oroscillatory motion of the crank is translated into linear motion of theconnecting rod.

The assembly of connecting rods around the side of the ship will cause adegree of turbulence and drag in their passage through the water tendingto slow up the ship and to obviate this undesirable tendency theconnecting rods may be contained in a channel within the ship. The crankpins of the various tins -associated with the assembly pass throughcurved slots in the ships side where they connect with their respectiveexible joints in the system of connecting rods in a similar manner tothe construction of Figure 4. An advantage of this construction is thatthe channel containing the connecting rod assembly is in eifect anadditional bilge stringer of a form contributing greatly to thestrengthening of the ship. Details of the construction are shown inFigures 5, 6 and 7, in which like reference characters refer to likeparts throughout the several views. Referring rstly to Figure 7 which isa traverse section of a part of the hull (on line A-A, Figure 5) in theregion of the b-ilge, fin 4 is attached to the hull as shown and is soproportioned that its extremity does not protrude beyond the projectionsof the ships side and bottom as indicated by the broken lines. Crank pin17 of fin 4 protrudes into the channel 26 with-in the hull throughcurved slot 27 where it connects with llexible coupling 19 unitingconnecting rods 20 and 20a (Figure 5). Channel 26 may be of weldedconstruction in steel and welded to the sides of the ship forwatertightness and strength. The channel is widened at a suitable pointX (Figure 5) to accommodate the watertight gland of Figure l0 associatedwith the n actuating shaft 22.

Figure 6 shows a part elevation of the ships hull in the region of tin4. In the figure, the broken lines represent the channel within thehull. Slot 27 cnt in the ships side enables crank pin 17 to pass intochannel 26 and connect with a flexible coupling (not shown) in theSystem of connecting rods located longitudinally within said channel.

Figure 8 shows a method of uniting two connecting rods by means of aflexible coupling to impart a degree of resilience between the rods soconnected. The flexible coupling 19 consisting of two halves e and f ismoulded in a suitable grade of hard rubber. The centre portion ispreferably in the form of a hollow sphere, the internal diameter(indicated by the broken line) being a working tit with respect to thespherical end or knuckle 1S of crank pin 17 (Figure l). The sphericalpart is provided with two oppositely facing cylindrical extensions orstubs 28 which are a squeeze t in the ends of the tubular connectingrods 20 and 20a. ln assembly, the two halves of the flexible couplingare placed so that the central portion encloses the aforementionedknuckle on the crank pin. The cylindrical extensions are then forcedinto the ends of the connecting rods and secured by through bolts 29. InFigure 9 an alternative construction is shown in which slots 29 aremoulded in the cylindrical extensions 28 and the ends of the hollowconnecting rods 20 and 20a are turned inwardly to engage said slots asshown in the figure. The ends of the connecting rods are furtherprovided with a number of longitudinal slots or saw-cuts (not shown) toenable the ends to be opened up or increased in diameter. To assemblethe flexible coupling in this construction the ends of the connectingrods are opened out by forcing in a conical tool for example. This willallow the cylindrical extensions of the exible coupling to pass easilyinto th ends of the connecting rods and for the inwardly turned ends ofsame -to register with slots. Clamping rings 3i) are then placed roundthe ends of the connecting rods and tightened by means of screws 31until the inwardly projecting ends of the rods are seated in slots 29.

I claim:

l. A ship stabilizer comprising a ships hull, a .plurality of stub axlesmounted outside the hull, spaced water-lubricated bearings mounted onthe stub axles, tins mounted on the bearings for rotation about the stubaxles, cranks secured to the tins, a connecting rod secured to thecranks for simultaneous operation of the ns and formed of sectionsconnected by moulded flexible joints which also engage the ends of thecranks, a watertight gland in the hull and operating means for theconnecting rod extending through the gland.

2. A ship stabilizer as claimed in claim l, in which the stub axles aremade only of such a strength that they will break ol in the event ofover-straining before damage is caused to the hull.

Pr., .e

5 3. A ship stabilizer comprising a ships hull, a plu- References Citedinthe file of this patent raliy Of. Stub aXleS mOllIled Outside the111111, the Stl'lb UNITED STATES PATENTS axles being made only of suchstrength that they w111 break off in the event of over-straining beforedamage gtucr ATulyl is caused to the hull, spaced water-lubricatedbearings 5 u pr' d th b l n td h b 2,550,752 Allan May 1, 1951 munte One Stu ax es, s mo'un e ont e eamngs Mar. 24

for rotation about the stub axles, actuating means mounted to form partof each fin and means extending FOREIGN PATENTS through the hull tooperate the actuating means. 10 496,524 Great Britain Dec. l, 1938

